Microsoft Visio 2010 : Creating and Using Shape Data Fields (part 5) - Shape Data Labels versus Names

6. Shape Data Labels versus Names

Shape Data fields actually have two names. Visio does its best to shield end users from this fact, but you will run into situations in which it helps to understand the nitpicky details.

Warning: This section is a bit technical, so you might choose to skip it or skim it quickly.

However, if you think Shape Data fields are the coolest, you plan on using them often in your Visio work, are interested in doing calculations with them, and want to link them to data using the Database Wizard, you need to understand how they are named.

Shape Data used to be known as Custom Properties until Visio 2007. You see vestiges of in the ShapeSheet, where you see that cells which hold Shape Data information are prefixed with “Prop.” If you search the Internet for information on Visio Shape Data, you will run into the term “Custom Properties” in older articles, and will probably find more information if you include the term in your search.

When you define a Shape Data field, note that you enter its name in a field called “Label.” If you turn on the Developer tab (via Customize the Ribbon), Visio switches to “developer mode” and adds extra elements to the user interface. In the Define Shape Data dialog, you see additional fields, one of which is the “Name” field.

Figure 6 compares the non-developer-mode dialog (left) with the developer-mode dialog (right).

Figure 6. The Developer-mode Define Shape Data dialog (right) shows more fields than the default. The ShapeSheet below shows the relationship between row Name and that of the Label.

In Figure 6, take a look at the Name field that appears just below Label. The Name is the row name of the Shape Data field, as represented in the ShapeSheet.

The ShapeSheet is how a developer views Visio shapes. It is an Excel-like spreadsheet that lives behind every Visio shape, “Developing Custom Visio Solutions.” Normally, you don’t need to go into the ShapeSheet, and you should probably stay away from it. But I’ve already warned you that this was a technical section, so have a glance at the ShapeSheet at the bottom of Figure 6.

Even though I’ve given the data fields nice names like “Power (Watts)” and “Bulb Type”, the fields are internally represented with dull automatic row names such as Prop.Row_1 and Prop.Row_3. You can see these row names in the developer version of the Define Shape Data dialog at right in Figure 6.

Visio tries to shield the average user from Row_1, Row_2, and Row_3 by showing only labels by default. However, if you try to map fields to a database using the (older) Database Wizard or try to do calculations with Shape Data fields, you run into them. This can make it hard to know what you’re mapping or calculating. If you have Visio 2010 Standard, the Database Wizard is your only data-linking option, so you’re even more likely to run into the problem.

Turning on the Developer tab on the Ribbon gives you a chance to change these names when defining Shape Data fields. For the light bulb shapes, you can change Row_1 to Power_W and Row_3 to Bulb_Type, for example. Note that row names can’t contain spaces, commas, colons, semicolons, and so on.

You don’t have to be a ShapeSheet developer to make use of this seemingly obscure knowledge. The insert field function lets you create calculations based on Shape Data fields using the Custom Formula option. To create custom formulas, you need to reference the row names, not the labels. And this feature is too cool to ignore, so let’s see how it works.

Creating a Simple Calculation Using Shape Data

For the intrepid who would like a bit more control, there is a function that allows you to specify the formatting of calculations. To show two decimal units for the kilowatt value, you can enter the following formula:

FORMAT(Prop.Power_W/1000,“0.00”)&“kW”